The history of Saudi Arabia’s gas programme goes back almost 40 years, and is enriched with achievements and growth. In 1975, the Kingdom initiated the Master Gas System (MGS) that quickly became operational with the commissioning of three major gas plants to process only the associated gas (AG) that is recovered with oil production.
In 1984, two non-associated gas (NAG) plants were introduced into the MGS. In 2001 and 2003, two more new ‘grass-root’ gas plants for the southern area fields were put fully on-stream to process only NAG followed by gas plant expansion along with a Natural Gas Liquid (NGL) recovery plant.
Furthermore, a sixth gas plant was put on-stream in 2010 to process only AG, and later in 2012 facilities were expanded to process the first offshore NAG and following that the seventh gas plant was added in 2015 to process additional NAG from new offshore gas fields. The future of the gas programme is bright with the addition of more fields and gas plants to significantly increase the amount of produced raw gas in the upcoming years.
The Gas Reservoir Management Department (GRMD) is responsible for the company’s NAG programme with hundreds of wells that produce billions of cubic feet of raw gas daily with hundreds of thousands of barrels per day (MB/D) of condensate. With over 120 professionals focused on developing the Kingdom’s NAG reserves, GRMD has thrived under the building blocks of attracting a talented and qualified national and international workforce, establishing a healthy and creative working environment, and empowering staff to make critical decisions to handle the challenges and workload required to meet the Kingdom’s future gas needs.
A large percentage of the development budget over the next decade is dedicated solely to the conventional gas programme to meet the increasing energy demand. By identifying a robust gas development programme, new technologies and the necessary staffing levels, the department is well positioned to meet these goals and objectives.
“GRMD is committed to the Energy to Kingdom initiative of the Accelerated Transformation Programme (ATP) for the gas programme’s role in identifying new gas resources and increasing reserves and gas supply,” said Adnan Al-Kannan, Manager of the Gas Reservoir Management Department (GRMD).
“The department continues to steward new technologies within the gas programme, in drilling, stimulation, and completion, to enhance production and increase reserves. Many new technologies, such as seismic imaging to identify ‘sweet spots’, long extended reach horizontal wells to improve reservoir contact, multi-stage fracture stimulation to enhance production from relatively tighter formations, underbalanced coiled tubing drilling to tap into productive layers, and evaluating the feasibility of using low-pressure systems to significantly decrease field abandonment pressures, and increase production and ultimate gas recovery.
“These are being utilised to produce gas that otherwise would not be recovered using conventional methods. These endeavours and continuous testing and application of novel technologies have increased success rate and significantly enriched Saudi Aramco’s gas programme.”
Meeting the technical talent requirement plays a major role in the expansion of the non-associated gas programme in new frontiers. GRMD has been one of the key proponents in attracting multidisciplinary talents from both national and international pool of specialists.
GRMD positioned itself to meet challenges by hiring the most talented work force possible and acquiring high-end petroleum engineering technology, software, and equipment.
“Expanding the life of existing fields through the introduction of innovative evaluation techniques and new technology applications is one of the focal areas of the department. GRMD closely collaborates with geoscientists, drilling, facility and production engineers, as well as completion, stimulation, and production specialists to ensure that overall well and field development criteria are followed and met.
“Ours is ‘Drill to Production’ approach – there has to be optimisation in every step along the journey to make endeavor successful,” said Zillur Rahim, senior petroleum engineering consultant & hydraulic fracturing team leader, GRMD.
Mike Hass, petroleum engineer consultant at GRMD, added: “Reservoir management engineers are key enablers in planning and optimising field development, maximising property value, evaluating production performance, ensuring reservoir health indices, and are responsible to supply and sustain the NAG production for the Kingdom.
“All GRMD engineers are specialised in general reservoir engineering as well as many other specialised petroleum engineering disciplines such as well completion and stimulation, rock and fluid properties, pressure transient testing, reservoir simulation, and production forecasting.”
The qualified young professionals are routinely trained in Saudi Aramco’s state-of-the-art Upstream Professional Development Centre (UPDC) and are also closely mentored by the senior GRMD staff to transfer the proper knowledge and training to meet the future challenges in producing oil and gas from highly complex reservoirs.
GRMD routinely conducts knowledge sharing events, mentoring initiatives, workshops, short courses, and hands on training for the engineers and technologists.
“The management is very keen and deeply involved in broadening employee knowledge base. On top of the in-house development plans, we frequently send out our engineers overseas for high education and training purposes; they add value when they return with knowledge and industry exposure,” says Al-Kanaan.
Development through technology
The delineation and deepening initiatives to tap conventional and tight gas resources in and around existing fields have resulted in the discovery of new reservoirs and adding reserves by extending the field limits.
Deepening selected wells to new horizons is a cost-effective method to assess new formations in existing fields and expand reserves portfolio. This strategy along with new discoveries and use of novel technology increased the non-associated gas reserves by 70% in the past decade.
The current yearly addition through the continuation of such strategies is to replace production and increase reserves cost effectively to help meet the Kingdom’s increasing energy requirement.
An example of a new technology application is underbalance coiled tubing drilling rigless that is a ‘game changer’ for the gas programme that has increased the total productivity of low rate gas producers by over billions of cubic feet of raw gas per day.
The rigless unit utilises slim drilling assemblies to place multi laterals within the reservoir while flowing the well and transferring the produced gas to the nearest processing facility throughout the drilling operation — eliminating flaring and protecting the environment.
This strategy also helps assessing reservoir quality through production rate, thereby maximising net pay interval. Over the past five years, many low rate gas wells were re-drilled with this application that delivered higher gas rates, reduced drilling time, and lowered unit development cost compared to conventional drilling.
Meeting Domestic Energy Requirement with Gas
The Peak Seasonal Production (PSP) Strategic Plan is to meet domestic power requirements by supplying additional gas during peak demand periods — to reduce burning crude oil — which has worked successfully by targeting prolific reservoirs, implementing best reservoir management practices.
It also optimises gas production priorities and spare plant capacity to minimise the volumes of supplemental crude oil burned for energy. Since starting the PSP programme in 2010, there has been more than 80% reduction in the volumes of supplemental crude oil burned amounting to millions of barrels of oil saved for export.
The goal is to fully offset the supplemental crude oil burning in the Eastern region in the coming years by capitalising on full continuous production from the new gas field developments, other new planned gas plants and increments, and fully utilising the dedicated PSP.
“Saudi Aramco has been exploring, developing and producing hydrocarbons from onshore fields for over 80 years, but it was not until 2011 when the first offshore non-associated gas field was put on production,” said Al-Kanaan.
“Saudi Aramco developed the first offshore gas field — located in one of the busiest oil tanker shipping areas in the world — in record time, only within five years after its discovery in 2006, from exploration to production.
Optimal drilling and completion strategy helped in fast-tracking the project. Subsequent to this first development, other giant offshore gas fields were discovered and developed. Due to the prolific nature of these fields, big bore, high pressure completions were used to ensure gas rates up to 300 MMSCFD per well.
The production is used for domestic consumption to meet the Kingdom’s energy needs for the foreseeable future, resulting in a significant reduction of crude oil burning that would otherwise be required to generate energy.”
Hydraulic Fracturing Industry Leader
“Multi-stage fracturing (MSF) in horizontal wells has been a major and significant improvement for Saudi Aramco’s gas programme, especially compared to dual lateral and vertical stimulated well completion methods,” revealed Rahim.
“The strategy includes drilling a well in the minimum in-situ stress direction, complete with an open-hole assembly comprised of injection ports and zonal isolation packers, and fracturing the well in stages.”
The induced fractures grow transverse to the wellbore, thereby staying independent and separated from one another and contributing to large reservoir/fracture contact area.
Some wells are also completed using conventional cemented liner assembly with cluster perforations and treated the same way.
GRMD initiated several environmental-friendly optimisation strategies, particularly in the use of clean stimulation fluids, to enhance the MSF technology that were tested successfully, thereby increasing well potential and sustainability.
Saudi Arabia today is internationally recognised in the field of hydraulic fracturing, contributing to its technical enhancement, and deriving immense benefits from its application.
The significant improvement of gas production and transforming low producing areas to commercially viable assets with the use of MSF has made this technology become very popular to the overall gas field development strategy.
Rahim is very optimistic with regards to the major impact MSF has brought in enhancing Saudi gas production and tapping tight gas. “Production has increased significantly since MSF campaign started – MSF compensates drilling additional wells thereby reducing overall development cost,” adds Rahim.
While speaking on technology improvement, he said, “since its inception, the MSF has made substantial progress in improving and optimising the conventional practices in both stimulation treatments and completion assemblies with the testing and use of high-strength proppant, retarded acids, emulsified systems, low polymer non-damaging fluids, visco-elastic fluids, advanced open-hole multistage completion assemblies, cased plug and perforation stimulation procedures with cluster perforations, and innovative sequential pumping operations to attain high fracture conductivity. While the open-hole completion is isolated in segments by mechanical or swellable packers, the plug and perforation operations are conducted through perforations in cased-hole, cemented completions with the use of mechanical plugs for intra-interval isolation. Current technology involve in evaluating self-degradable balls, ball-seats, and plugs to avoid post-frac well intervention and achieve higher efficiency in conducting fracturing operations.
“In parallel to advancing fracturing pumping operations and completion assemblies, GRMD is also working on a number of other improvements,” Haas adds.
“Among them is the real-time geo-mechanics that predicts formation pressure and possible well caving or hole breakdown events while drilling in the minimum in-situ stress direction so that those challenges can be mitigated, use of low gel loading and optimal chemical concentration to reduce formation damage yet providing adequate fluid viscosity in fracturing operations, and maintaining a clean and conductive fracture to sustain long-term well production rate. These enhancements help creating and propagating uniform fractures that are transverse to the wellbore, independent and highly conductive, fast and efficient post-treatment cleanup, and ensure large reservoir/fracture contact area, thereby increase retained proppant permeability and gas production.
Use of improved chemical systems for a subsequent cleanup on few already fractured wells that were showing low productivity revived them at a higher sustained rate.”
Simulation modeling is routinely performed to compute the number of optimal transverse fractures needed to achieve desired well production rate and the dimensions, properties, and spacing of these induced fractures.
The stress shadow effects are included during modeling that ensures realistic fracture growth and dimensions. Rigorous modeling with the best available data has enabled the engineers to design and select the optimal completion and stimulation practices, optimise well placement and spacing, and attain higher well productivity.
This model also multi-well simulation modeling is used to understand production impact from offset wells and predict candidate well rate.
“The use of high strength proppant to counter in-situ stress that would otherwise crush the proppant in deep, high pressure and high temperature wells has proven to sustain fracture conductivity overcoming gel damage, fines migration, embedment, and proppant degradation with time,” Rahim said, adding, “In essence, MSF technology and its application has made a great impact on overall gas program transforming low rate gas wells high producers and commercial thereby making gas field development economically attractive.”
